The acceptability and feasibility of using a 3D body size scale to initiate conversations about weight in toddlerhood: a mixed‐methods study

Health Care Professionals struggle to initiate conversations about overweight in toddlerhood. A novel 3D body size scale (3D BSS) may facilitate engagement with this topic during pediatric appointments.

retrospective analyses of children in Germany, nearly 90% of 3-yearold children with a body mass index (BMI) in the obese range (BMI > 99th percentile) continued to be affected by overweight or obesity into late adolescence (n = 51 505). 2 Moreover, adolescents with obesity showed the greatest acceleration in their BMI between the ages of 2 and 6, highlighting this period as critical for children's weight development. In order to address the development and sustainment of excess adiposity in childhood, obesity prevention efforts need to start early. 3 Overweight in early childhood can be difficult to identify by sight alone. Both caregivers and Health Care Professionals (HCPs) often do not recognise overweight in young children. 4 In a review of 51 experimental studies, 86% of parents with 2 to 6-year-old children did not recognise overweight in their child. 5 Similarly, a study with HCPs showed that 74-79% of HCPs misclassified toddlers with overweight as having a healthy weight. 6 These findings can be explained by the visual normalisation theory of overweight, proposing that the "threshold" for what is considered overweight has increased in line with population prevalence leaving overweight as "unseen". 7 The misperception of weight status carries significant implications, with parents less likely to adopt healthy lifestyle changes for children when excess weight goes unrecognised. 8 At present, HCPs rely on the WHO Standard Growth Charts 9 to track and communicate childhood weight development. These charts are widely implemented 10 but parents report confusion towards them due to their numerical complexity. 11 In one experimental study (n = 1000) 77% of parents incorrectly interpreted the results of growth charts, despite 79% reporting familiarity with the tool. 12 Hence, growth charts alone may be insufficient to engage caregivers in conversations about bodyweight. 13 A newly developed 3D body size scale (3D BSS) provides a visual representation of body shape variation across the weight spectrum and may help support such conversations. 14 The 3D BSS presents anatomically correct models of a female and male child, morphed from 211 body scans, ranging from underweight to very overweight categories. In contrast to previous visual models of weight status which have largely relied on subjective artists' sketches of differing body size, the 3D BSS is the first to align with the British 1990 child growth reference data, making it suitable for use in the UK. 15 In a previous study, the 3D BSS of 4-5-year-olds was sent to parents alongside the National Child Measurement Programme (NCMP) feedback letter and was shown to double the uptake of a child-weight-management service. 16 Additional qualitative work undertaken during the development of the 3D BSS demonstrated acceptability and utility of the 3D BSS for facilitating engagement between parents (n = 33) and health care professionals. 14 These findings suggest that applying a similar 3D BSS for toddlers into routine pediatric conversations may aid understanding of weight development and thereby increase engagement with beneficial health behaviours.
Prior to such development and implementation, it is crucial to evaluate the acceptability and feasibility of delivering the 3D BSS to families of toddlers and explore potential risk for negative psychosocial consequences. There has also been limited research exploring parental preferences for early weight-related conversations, despite the routine nature of these discussions through the UK-wide 2-year Child Development Check. 17 Therefore, the current "Healthy Toddler Study" (HTS) aimed to explore caregivers perspectives towards integration of a 3D BSS into pediatric appointments. The current paper will highlight relevant barriers and facilitators to engagement with the 3D BSS, as well as with conversations regarding child weight patterning more generally. A mixed-methods approach was employed to explore the following research questions:

| Participants
Participants for the current study had to be the primary guardian of at least one 2-to-4-year-old child and reside in the UK. Recruitment occurred through snowball sampling on social media (Facebook, Twitter). A separate group of participants (n = 3), subject to the same inclusion criteria, were recruited to pilot the study materials. Following this pilot, 68 eligible participants expressed interest, of which 38 completed the HTS procedures. Participants provided informed consent and were provided £25 vouchers.

| Materials & Procedure: Quantitative Phase
Participants (n = 38) were asked to complete two online questionnaires on REDcap, a secure online survey management platform. 19 The baseline questionnaire was provided through an email link a week before the interview, and the second questionnaire directly postinterview. Questionnaires were completed remotely online. The baseline questionnaire collected demographic and anthropometric information including caregiver sex, age, height, weight, educational attainment, ethnicity and number of children, as well as their toddler's age, sex, height, and weight. In the post-interview questionnaire, participants were asked to i) rate the acceptability of being offered the 3D BSS by a HCP (7-point Likert Scale, "very acceptable" to "very unacceptable") and ii) rate whether they felt their understanding of child weight development had improved after being introduced to the 3D BSS (7-point Likert Scale; "very improved" to "very decreased"). were undertaken over the phone, with two interviews undertaken inperson to suit the participants' preference. The researcher read aloud to participants a vignette describing a fictional routine 2-year Child Development Check appointment. 17 The vignette depicted this appointment with a mother, a female toddler and a Health Visitor for all participants. For the full vignette see Figure S1. Participants were asked to respond how they believed the mother in the vignette would feel and act in the story, exploring the sensitive topic of toddler weight in a less personal manner. 20 For the full interview schedule see

| Visual study pack
Participants received an electronic "HTS study pack" over email (n = 36) or on paper (n = 2), depending on the setting of interview. See Figure S4. This pack included two visual prompts: (1) a UK-WHO growth chart for girls 0-4 9 and (2) the female 3D BSS of 4-5-year-old children. This 3D BSS was developed by obtaining KX-16 3D surface body scans and anthropometric measurements of 4-5 -year-old children (n = 211). These scans were subsequently morphed, using V5 and M5 morphs (from www.daz3d.com) to create models representative of each BMI category and intended to depict children of no specific ethnicity. For the full 3D BSS see Figure S4. 14 When introduced to the 3D BSS, participants were directed towards the image on the 3D BSS relevant to their allocated weight condition (underweight, healthy weight, overweight).
The 3D BSS of 4-5-year-old children was provided as an equivalent stand-in visual tool, given that at the time of the present HTS study, the 2-3-year-old BSS images were under development. The insights of the present HTS study were intended to inform the design and refinement of the toddler 3D BSS. As this study aimed to explore caregivers' general acceptance of a 3D BSS in the context of a routine consultation, as opposed to their views of the presentation, design and appearance of the tool itself, it was decided this stand-in tool was adequate. Moreover, during piloting of the study materials, the older age of the 3D BSS was undetected (n = 3). The insights of the present HTS study were also used to refine the design of the toddler 3D BSS. For further details of how the 3D BSS was presented to study participants, see Figure S2.

| Analyses
Verbatim transcription of 38 interviews was undertaken by an external transcription company (Devon Transcriptions Ltd.). Transcripts were analysed using deductive thematic analysis, using a realist epistemology, and adhered to the stepped approach as set out by Braun and Clarke. 21 Interview transcripts were coded independently by two researchers (KT and AS), and subsequent inter-rater reliability indicated fair to good agreement (α = 0.66) in a double coded subset (n = 8, 21%). NVivo V12 22 was used to store and organise codes throughout the analyses. Acceptability was measured using a 7-point acceptability Likert-scale which was treated as continuous, assuming equidistance between points. 23 One-way ANOVA's were conducted to compare differences in mean 3D BSS acceptability scores by i) the weight status of the toddler depicted in the vignette and ii) the weight status of the caregiver being interviewed. To account for potential presentation order effects, the order of chart presentation to the vignette parent (UK-WHO growth chart first vs 3D BSS first) was randomly allocated. This final sample size was sufficient to achieve statis-

| Characteristics of study participants
A sample of 38 caregivers were recruited, consisting of 35 mothers and 3 fathers (8%). Participants were mostly of white ethnicity (n = 31; 81%) and highly educated (n = 34; 89% with university-level education). Participant demographic details are presented in Table 1.
Few caregivers (n = 2; 5%) considered the 3D BSS as "moderately unacceptable" or "very unacceptable". There was a no effect of the vignette toddler's weight status (P = 0.62) or caregivers weight status (P = 0.74) on 3D BSS acceptability. Full details of acceptability scores by weight status condition are shown in Table 2.

| Thematic analysis
Seven key themes were identified from deductive thematic analysis.
These consisted of four key "barriers" and three "facilitators" concerning caregivers' acceptance of the 3D BSS as a visual tool for use during routine pediatric appointments. These themes and subthemes are represented in Figure 1.

| Barrier 1: Weight is a sensitive topic
Caregivers expressed the desire to discuss toddler weight development with a relevant and knowledgeable HCP (Quote 1; Q1). Many parents however voiced concern that childhood weight is a sensitive issue which should be discussed with care (Q2). Parents spoke of feelings such as guilt, defensiveness, and worry, which arise when told of

| Acceptability of the 3D BSS
Caregivers found the 3D BSS to be a "moderately" to "very" (n = 32/ 38; 84.2%) acceptable resource. Acceptability did not differ by the weight status of the child in the vignette or the caregivers interviewed. Acceptability was contingent upon a number of barriers and facilitators.

| Barriers to the acceptability of the 3D BSS
Findings from the present study emphasized that overweight in toddlerhood is a highly sensitive matter where caregiver worry and defensiveness may influence discussion. Previous findings show that such 'defensiveness' can lead nurses to avoid weight-related conversations. 25

| Facilitators to the acceptability of the 3D BSS
Participants believed the 3D BSS provided a welcome opportunity to discuss toddler weight development. 26

| Limitations and Strengths
Various strengths and limitations must be considered in relation to this study. First, the mixed methods approach allowed for integration T A B L E 9 Quotes relating to Facilitator 3: Tailor conversations to the individual needs of families Nonetheless, this study benefits from its novel focus on early childhood, as early weight development is predictive of future adiposity. 2 In line with current clinical guidelines, discussion of weight development and regular plotting of BMI from early childhood is warranted. 30-32 3D BSSs offer potential as a novel means for facilitating such conversations which in turn could lead to greater promotion of strategies to counter rapid weight gain in early childhood. The 3D BSS could be integrated into existing frameworks for weight monitoring. Parents often do not "see" their child's weight status objectively, but the 3D BSS may help overcome this issue by enabling parents to see their child's weight status in context. Clearer perception of their child's weight may also increase caregivers' receptivity to information on intervention and prevention strategies. Moreover, a considerable proportion of health personnel are uncomfortable with initiating conversations about a child's weight status. Being able to use a hard copy or digital version of the 3D BSS (eg, on a tablet) may provide a practical and supportive tool to broach the sensitive topic of child weight in the context of a routine healthcare appointment. 33

| CONCLUSION
The present feasibility study indicated that 3D Body Size Scales may be an acceptable tool to engage caregivers in conversations regarding early childhood weight development, if they are accompanied by tai-